Classification and effectiveness of different thickeners(2)

1.3. Sodium alginate.

Also known as sodium fucoidan, sodium alginate, fucoidan. It is a linear molecule of acidic polysaccharide, consisting of α-L-gulo-gulo aldehyde and β-D-manno aldehyde linked by 1,4 glycosidic bonds. The washed kelp was dissolved in sodium carbonate solution, diluted and filtered with water and inorganic acid was added to precipitate out the alginate. After centrifugation and separation, it is dehydrated in methanol, bleached, neutralised with sodium carbonate or baking soda, pressed to remove the methanol, dried and crushed to produce sodium alginate. Sodium alginate is a white or light yellow powder, almost odourless, soluble in water. It is hygroscopic and its viscosity is stable at pH 5 to 10, but increases significantly at pH less than 4.5 and precipitates at pH less than 3. Monovalent ions can reduce viscosity, more than 8% of sodium chloride will lose viscosity due to salt precipitation.

Sodium alginate has the effect of causing cholesterol to be expelled from the body, inhibiting the absorption of heavy metals in the body, having physiological effects such as lowering blood sugar, not being absorbed by the body, and having a dietary fibre effect. Sodium alginate interacts with calcium ions in cow's milk to produce calcium alginate, which forms a homogeneous jelly, a feature not found in other stabilisers. Calcium alginate is very good at maintaining the shape of ice cream, especially for long term storage, and is most effective in preventing volume shrinkage and gritting of the tissue. It can also be used as a thickening agent for canned jams.

1.4. pectin

A white to light yellowish-brown powder with a slightly peculiar odour. Dissolves in 20 times water to form a viscous liquid. Insoluble in ethanol and other organic solvents, it is more soluble in water when moistened with ethanol or glycerine or sucrose syrup and mixed with three or more times granulated sugar. It is more stable to acidic solutions than to alkaline solutions.

Pectin can be used in jams in quantities of 2 g/kg or less. It can be used in chocolate, confectionery and other foodstuffs, as a stabiliser for cold drinks such as ice cream and ice-cream, as well as to prevent hardening of pastries and to improve the quality of cheese.

2. Chemically synthesized thickeners

2.1. Sodium carboxymethyl cellulose

CMC is a white powder, easily dispersed in water, hygroscopic, viscosity rises significantly below 20℃, heated above 80℃, viscosity decreases, viscosity remains unchanged for a week at 25℃. Dry CMC is stable and can be biodegraded in solution. It is an acidic polysaccharide and its viscosity decreases significantly when the pH is outside 5-10. It is generally used in foods with a pH range of 5-10. It can also be used in protein drinks such as fruit milk, powdered food, sauces, bread and meat products, etc. The price is relatively cheap.

2.2. Carboxymethyl starch (sodium)

Also known as sodium starch ethanoate, CMS is an anionic starch ether, a polyelectrolyte that dissolves in cold water.CMS is a starchy white powder, odourless and tasteless, which dissolves in water at room temperature to form a transparent viscous colloidal solution. The aqueous solution is acidic and suitable for use under alkaline conditions.

CMS can be used as a suspending agent in solid drinks, with no floating matter, no stratification and no precipitation after washing and dissolving; it also has the effect of suspension and stabilization in drinks; in the production of instant noodles, it can make the noodles taste lubricious, easy to separate and shorten the rehydration time.